Composition for dyeing keratin fibers comprising a direct dye that carries a disulfide / thiol function, a low ethoxylated or non-ethoxylated fatty alcohol, a cationic surfactant, an alkaline agent and a reducing agent
The invention relates to a process for dyeing and/or lightening keratin fibers such as the hair, using i) at least one direct dye bearing a disulfide, thiol or protected-thiol function and ii) at least one sparingly or non-ethoxylated fatty alcohol, iii) at least one cationic surfactant, iv) at least one alkaline agent, and v) at least one reducing agent. The invention also relates to a composition comprising the ingredients i) to v), to the use of the combination of i), ii), iii), iv) and v) for the dyeing and/or lightening of keratin fibers, and to a multi-compartment kit comprising the ingredients i) to v). The dyeing process and the composition according to the invention especially afford a long-lasting coloration on keratin fibers, which is strong, chromatic and/or homogeneous, with or without the use of an oxidizing agent.